Battery module, method for manufacturing battery module, and electronic device

ABSTRACT

A battery module with high impact resistance is provided. A battery module using an elastic body such as rubber for its exterior body covering a battery is provided. A bendable battery module is provided. As the exterior body covering a battery, an elastic body such as rubber is used, and the exterior body is molded in two steps. First, a first portion provided with a depression in which a battery is stored is molded using a first mold. Next, a battery is inserted into the first portion. Subsequently, second molding is performed using a second mold so as to fill an opening of the depression in the first portion, so that a second portion is formed. The second portion serves as a cover for closing the opening of the depression in the first portion. The second portion is formed in contact with part of the electrodes in the battery and part of an end portion of the second exterior body in the battery.

TECHNICAL FIELD

One embodiment of the present invention relates to a battery. Oneembodiment of the present invention relates to a battery moduleincluding a battery. One embodiment of the present invention relates toa battery that is attachable to an electronic device. One embodiment ofthe present invention relates to an electronic device that is driven bya battery.

Note that one embodiment of the present invention is not limited to theabove technical field. Examples of the technical field of one embodimentof the present invention disclosed in this specification include asemiconductor device, a display device, a light-emitting device, a powerstorage device, a memory device, an electronic device, a lightingdevice, an input device, an input/output device, a driving methodthereof, and a manufacturing method thereof.

BACKGROUND ART

Portable information terminal devices typified by smartphones and tabletterminals have been actively developed. Such electronic devices arerequired to be lightweight and compact, for example.

In recent years, wearable electronic devices (also referred to aswearable devices) especially have been under active development.Examples of wearable devices include a watch-type device worn on an arm,a glasses-like or a goggle-type device worn on a head, and anecklace-type device worn on a neck. For example, a watch-type deviceincludes a small-sized display instead of a conventional watch dial toprovide the user with various information in addition to the time. Suchwearable devices have attracted attention to the medical use, the usefor self-health management, or the like and have been increasingly putinto practical use.

Mobile devices include secondary batteries that are capable of beingrepeatedly charged and discharged, in many cases. Wearable devicesparticularly include small-sized secondary batteries; thus, secondarybatteries should be lightweight and compact and should be capable ofbeing used for a long time.

For example, Patent Document 1 discloses a wearable device including aflexible secondary battery in which a film is used as its exterior body.

REFERENCE Patent Document

[Patent Document 1] Japanese Published Patent Application No.2015-038868

DISCLOSURE OF INVENTION

A second battery might cause heat generation or catch fire when itsexterior body is damaged, and thus the second battery is generallycovered with a hard exterior body even in the case where a film is usedfor the exterior body. However, this structure has a problem in thatchange in shape of the second battery due to bending or the like is notassumed and the place where the secondary battery is provided is limitedin the case of being mounted on an electronic device.

An object of one embodiment of the present invention is to provide abattery module which has high impact resistance and can be mounted on orconnected to an electronic device.

Another object of one embodiment of the present invention is to providea battery module using an elastic body such as rubber for its exteriorbody covering a battery. Another object of one embodiment of the presentinvention is to provide a bendable battery module.

Another object of one embodiment of the present invention is to providea battery module which can be used as a wearing tool for an electronicdevice. Another object of one embodiment of the present invention is toprovide a battery module which can be used as a bendable wearing tool.

Another object of one embodiment of the present invention is to providea battery module in which a problem such as damage to a battery due totoo much bending is suppressed. Another object of one embodiment of thepresent invention is to provide a battery module in which the range ofbending is limited.

Another object of one embodiment of the present invention is to achievean electronic device which is capable of being used for a long time.Another object of one embodiment of the present invention is to providean electronic device, a battery module, or the like having a high designproperty. Another object of one embodiment of the present invention isto provide a battery module which can be easily attached to and detachedfrom an electronic device. Another object of one embodiment of thepresent invention is to provide an electronic device or a battery modulehaving high water resistance. Another object of one embodiment of thepresent invention is to provide a novel battery module or a novelelectronic device.

Another object of one embodiment of the present invention is to providean electronic component having high impact resistance or a moduleincluding the electronic component.

One embodiment of the present invention is a battery module including afirst exterior body and a battery. The battery includes a secondexterior body, a positive electrode, a negative electrode, anelectrolyte, and a pair of tabs. The positive electrode, the negativeelectrode, and the electrolyte are positioned in the second exteriorbody. The pair of tabs are provided so as to project outside the secondexterior body. The first exterior body includes an elastic material. Thefirst exterior body includes a first portion, a second portion, and aspace surrounded by the first portion and the second portion. The secondexterior body is provided in the space. The first portion and the secondportion are bonded to each other. The second portion is in contact withpart of the tabs and an end portion of the second exterior body.

In the above, it is preferable that the first portion and the secondportion include the same material and that the first portion and thesecond portion be bonded directly to each other.

In the above, it is preferable that the volume or the surface area ofthe second portion be smaller than that of the first portion.

In the above, it is preferable that the second exterior body have afilm-like shape and that the second exterior body change its shape alongthe first exterior body when the first exterior body changes its shape.

In the above, it is preferable that the first exterior body include aprotection member. The protection member preferably include a thirdportion covering one of two surfaces of the second exterior body, whichare opposite to each other, and a fourth portion covering the other. Itis preferable that the third portion and the fourth portion each have aplate-like shape and change its shape along the first exterior body.

It is preferable that the third portion and the fourth portion of theprotection member be bonded to each other on the second portion side ofthe first exterior body.

It is preferable that the third portion and the fourth portion of theprotection member have different lengths.

In the above, it is preferable that the first portion of the firstexterior body include slits into which the third portion and the fourthportion of the protection member fit slidably.

In the above, it is preferable that the first exterior body have abelt-like shape and a region with a thickness less than or equal to 5mm.

In the above, it is preferable that the battery module include a circuitboard. The circuit board preferably includes terminals electricallyconnected to the tabs. The second portion of the first exterior body ispreferably provided so as to cover the tabs and at least part of thecircuit board.

The circuit board preferably includes a protection circuit.

In the above, it is preferable that the battery module include a frame.The frame preferably includes a material having higher rigidity than theexterior body. The frame preferably includes a first terminal and asecond terminal. The first terminal is a terminal electrically connectedto the tab, and the second terminal is a terminal electrically connectedto the first terminal. The first portion of the first exterior body ispreferably provided so as to cover part of the frame and part of thefirst terminal. It is preferable that at least part of the secondterminal be exposed.

Another embodiment of the present invention is an electronic deviceincluding a housing. The housing preferably has a shape to be fittedinto the frame and includes a third terminal electrically connected tothe second terminal when the housing fits into the frame.

Another embodiment of the present invention is a method formanufacturing a battery module including a battery and a first exteriorbody covering the battery, which includes a first step, a second step, athird step, and a fourth step. The first step is a step of preparing abattery including a second exterior body and a pair of electrodes. Thesecond step is a step of forming a first portion including a depressionby molding a first material using a first mold. The third step is a stepof inserting the battery into the depression from the opening edge sideso that part of the electrodes projects outside the opening edge of thedepression. The fourth step is a step of forming the first exterior bodyin which the first portion and the second portion are bonded to eachother in such a manner that the second portion which seals the openingedge of the depression is formed by providing the first portion intowhich the battery is inserted in a second mold and molding a secondmaterial using the second mold. Here, the second portion is formed sothat it is in contact with the end portion of the second exterior bodyand part of the electrodes is exposed at the outside of the secondportion.

In the above manufacturing method, the electrodes are each preferablyany of the tab projecting from the second exterior body and a terminalelectrically connected to the tab.

In the above manufacturing method, the first material is preferably thesame as the second material.

In the above manufacturing method, it is preferable that a millablematerial be used as the first material and the second material and thatthe first portion and the second portion be formed by direct pressuremolding, direct pressure injection molding, or injection molding.

It is preferable that a liquid material or a paste-form material be usedas the first material and the second material and that the first portionand the second portion be formed by injection molding.

According to one embodiment of the present invention, a battery modulewhich has high impact resistance and can be mounted on or connected toan electronic device can be provided.

According to one embodiment of the present invention, a battery moduleusing an elastic body such as rubber for its exterior body covering abattery can be provided. According to one embodiment of the presentinvention, a bendable battery module can be provided.

According to one embodiment of the present invention, a battery modulewhich can be used as a wearing tool for an electronic device can beprovided. According to one embodiment of the present invention, abattery module which can be used as a bendable wearing tool can beprovided.

According to one embodiment of the present invention, a battery modulein which a problem such as damage to a battery due to too much bendingis suppressed can be provided. According to one embodiment of thepresent invention, a battery module in which the range of bending islimited can be provided.

According to one embodiment of the present invention, an electronicdevice which is capable of being used for a long time can be achieved.According to one embodiment of the present invention, an electronicdevice, a battery module, or the like having a high design property canbe provided. According to one embodiment of the present invention, abattery module which can be easily attached to and detached from anelectronic device can be provided. According to one embodiment of thepresent invention, an electronic device or a battery module having highwater resistance can be provided. According to one embodiment of thepresent invention, a novel battery module or a novel electronic devicecan be provided.

According to one embodiment of the present invention, an electroniccomponent having high impact resistance or a module including theelectronic component can be provided.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A to 1E illustrate a structure example of a battery module of anembodiment and a method for manufacturing the battery module of anembodiment.

FIGS. 2A to 2C illustrate a structure example of a battery module of anembodiment and a method for manufacturing the battery module of anembodiment.

FIGS. 3A to 3E illustrate a structure example of a battery module of anembodiment and a method for manufacturing the battery module of anembodiment.

FIGS. 4A to 4C illustrate structure examples of a battery and a batterymodule of an embodiment.

FIGS. 5A and 5B illustrate a method for manufacturing a battery moduleof one embodiment.

FIGS. 6A1 to 6A3, 6B1, 6B2, 6C1, and 6C2 illustrate a structure exampleof a battery module of an embodiment.

FIGS. 7A1, 7A2, 7B1, 7B2, 7C1, and 7C2 illustrate a structure example ofa battery module of an embodiment.

FIGS. 8A1 to 8A3, 8B1, 8B2, 8C1, and 8C2 illustrate a structure exampleof a battery module of an embodiment.

FIGS. 9A to 9C illustrate structure examples of a battery module and anelectronic device of an embodiment.

FIGS. 10A to 10C illustrate structure examples of a frame and anelectronic device of an embodiment.

FIGS. 11A to 11C illustrate a method for manufacturing a battery moduleof an embodiment.

FIGS. 12A to 12E illustrate a method for manufacturing a battery moduleof an embodiment.

FIG. 13 illustrates a structure example of a secondary battery of anembodiment.

FIGS. 14A and 14B illustrate a method for manufacturing a secondarybattery of an embodiment.

FIGS. 15A to 15C illustrate a method for fabricating a secondary batteryof an embodiment.

FIGS. 16A and 16B illustrate a method for fabricating a secondarybattery of an embodiment.

FIGS. 17A and 17B illustrate a structure example of a secondary batteryand its fabrication method of an embodiment.

FIGS. 18A and 18B illustrate a method for fabricating a secondarybattery of an embodiment.

FIGS. 19A to 19D illustrate a structure example of a battery of anembodiment.

FIGS. 20A and 20B are photographs of a battery module of an embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments will be described in detail with reference to the drawings.Note that one embodiment of the present invention is not limited to thefollowing description, and it will be readily appreciated by thoseskilled in the art that modes and details of the present invention canbe modified in various ways without departing from the spirit and scopeof the present invention. Thus, the present invention should not beconstrued as being limited to the description in the followingembodiments and example.

Note that in structures of the present invention described below, thesame portions or portions having similar functions are denoted by thesame reference numerals in different drawings, and a description thereofis not repeated. Furthermore, the same hatching pattern is applied toportions having similar functions, and the portions are not especiallydenoted by reference numerals in some cases.

Note that in each drawing described in this specification, the size, thelayer thickness, or the region of each component is exaggerated forclarity in some cases. Therefore, the size, the layer thickness, or theregion is not limited to the illustrated scale.

Note that in this specification and the like, ordinal numbers such as“first,” “second,” and the like are used in order to avoid confusionamong components and do not limit the number.

Embodiment 1

One embodiment of the present invention is a battery module including abattery and a first exterior body covering the battery.

The battery includes a positive electrode, a negative electrode, anelectrolyte, and a second exterior body covering them. Furthermore, thebattery includes a pair of tabs. The pair of tabs are electricallyconnected to the positive electrode and the negative electrode andproject outside the second exterior body. The positive electrode and thenegative electrode each include a current collector and an activematerial. The battery may include a separator which prevents anelectrical short-circuit between the positive electrode and the negativeelectrode. The electrolyte may be an electrolyte solution or a solidelectrolyte.

When a film-like material is used for the second exterior body, thebattery can have flexibility.

The first exterior body is provided to cover the battery and has afunction of protecting the battery. When an elastic body such as rubberor an elastic resin is used as the first exterior body, the impactresistance of the battery module can be improved.

The first exterior body may have a shape capable of being used for awearing tool for a wearable device. Typically, the first exterior bodymay have a shape of a band (also referred to as a belt or a strap) of awatch-type device. Thus, the battery module can be used as a powersupply (a main power supply or an auxiliary power supply) for thewearable device.

Here, in the case where rubber or an elastic resin is molded into anarbitrary shape using a metallic mold or the like, a high pressure needsto be applied to the material. When rubber or the like is molded in astate where a structure is provided in the metallic mold, a highpressure is isotropically applied to the structure. Therefore, in thecase where the first exterior body is molded in a state where thebattery is provided in the metallic mold, the battery changes its shapeand is damaged due to the pressure in some cases. Accordingly, it isdifficult to mold rubber or the like as the first exterior body coveringa battery particularly when the battery includes a film for the secondexterior body.

Furthermore, when rubber or the like is molded, a high temperature isneeded in order to soften the material, and in order to cause across-linking reaction of the material or thermally cure the material.When the battery is provided in the metallic mold at this time, thebattery may deteriorate due to the heat. Accordingly, not only in thecase of the battery using a film for the second exterior body but alsoin the case of a battery using a material having relatively highrigidity in the second exterior body, it is difficult to mold rubber orthe like so as to cover the battery.

In view of the above, in one embodiment of the present invention, thefirst exterior body is molded in two steps (by first molding and secondmolding). First, a first portion provided with a depression for storingthe battery is molded using a first mold (the first molding). The shapeof the first portion can be referred to as a bag-like shape having apocket for storing the battery, and an opening of the depression (thepocket) is formed. The size of the opening of the depression can bedetermined in consideration of the width and the height of the batteryand is preferably as small as possible.

When the pocket (the depression) is formed in the first portion inadvance and the shape of the opening and the shape of the pocket areformed in accordance with the shape of the battery, the battery can beprovided in a predetermined position in inserting the battery, and thusmisalignment between the first exterior body to be formed and thebattery can be prevented. Given that the battery is bent in onedirection, for example, it is particularly important to control thepositions of the first exterior body and the battery precisely.

Next, the battery is inserted into the first portion. At this time, thebattery is inserted so that part of the electrodes (the tabs, orelectrodes of a circuit board or the like, to which the tabs areconnected) of the battery is positioned outward from the opening edge ofthe depression in the first portion.

Subsequently, second molding is performed using a second mold so as tofill the opening of the depression in the first portion, so that asecond portion is formed. The second portion serves as a cover forclosing the opening of the depression in the first portion. The secondportion is formed in contact with part of the electrodes in the batteryand part of an end portion of the second exterior body of the battery.It is preferable to form the second portion in the second molding so asto avoid the position where the positive electrode and the negativeelectrode of the battery are provided. Thus, in molding the secondportion, a pressure can be prevented from being applied to a mainportion of the battery, and thus the battery can be prevented fromchanging its shape or being damaged. The second portion is preferablyformed in contact with a sealing portion of the battery on the tab side(also referred to as a top sealing portion) and the vicinity thereof inthe case where a film is used for the second exterior body of thebattery.

In the case where a high temperature is needed in molding rubber or thelike, the first exterior body is molded in two steps as described above,in which case the battery is exposed to a high temperature only in oneof the two steps. Accordingly, the battery can be prevented fromdeteriorating in molding the first exterior body.

Thus, the first exterior body in which a space is formed can be molded.In the first exterior body, the first portion and the second portion arebonded directly to each other. A boundary (a parting line) is formedbetween the first portion and the second portion in some cases.

In the battery module formed in this manner, the battery and the firstexterior body are fixed by the second portion. That is, the battery issealed in the first exterior body in a state where part of the batteryin contact with the second portion is fixed and the other part is notfixed. Since the battery is not fixed to the first portion, when thefirst portion changes its shape, for example, is bent, the battery andthe exterior body can change their shapes independently from each other.In the case where the battery is bonded to the first portion, forexample, stress is applied to the battery due to change in the shape ofthe first portion. In contrast, since the battery is not bonded to thefirst portion of the first exterior body in the battery module of oneembodiment of the present invention, the first exterior body can changeits shape by weaker force.

The battery module of one embodiment of the present invention and amethod for manufacturing the battery module are described below morespecifically.

STRUCTURE EXAMPLE 1

Here, an example of a band-like battery module which is suitable for awatch-type electronic device is described. Note that it is needless tosay that battery modules having a variety of shapes can be manufacturedby a method described below depending on the shape of a mold.

FIG. 1A is a schematic cross-sectional view of a mold 50 a for molding afirst portion 21 of an exterior body 20 in a battery module 10illustrated in FIG. 1E. The mold 50 a includes an upper mold 51 a, alower mold 51 b, a core 53, a core 54 a, a core 54 b, and the like. Inthe upper mold 51 a, an injection hole 55 a for injecting a material isprovided. Note that, in addition to the injection hole 55 a, a vent holeis actually provided in the upper mold 51 a or the lower mold 51 b. Thevent hole is not always provided.

The core 53 is a member for forming the depression in the molded firstportion 21. The core 54 a and the core 54 b are each a member forforming a through hole in the molded first portion 21. These cores areeach also referred to as a core cylinder or the like in some cases.

A material is molded using the mold 50 a illustrated in FIG. 1A, so thatthe first portion 21 illustrated in FIG. 1B can be formed.

As a method for molding the first portion 21, a molding method using asolid material or a semisolid material (collectively also referred to asa millable material) or a molding method using a liquid material(including a paste material) can be used. As a molding method using amillable material, direct pressure molding (also referred to ascompression molding), direct pressure injection molding (also referredto as transfer molding), injection molding, or the like can be given. Asa molding method using a liquid material, injection molding can be givenand is also referred to as a liquid injection molding (LIM) method insome cases.

The mold 50 a illustrated in FIG. 1A is suitable for direct pressureinjection molding. A material is provided over the upper mold 51 a, anda mold for pressing is pressed from thereover, whereby the material canbe injected from the injection hole 55 a. Note that the position or theexternal shape of the injection hole in the mold 50 a may be changed asappropriate depending on a molding method.

As a material to be molded, an elastic material can be favorably used.When the battery 30 described later is surrounded by an elastic body,the battery module 10 can have high impact resistance (see FIG. 1E).Furthermore, the battery module 10 capable of being wound around an armor the like can be obtained when a bendable battery is used as thebattery 30.

As a rubber material, a thermosetting material can be favorably used.When a thermosetting rubber material is used, a product which has highheat resistance and can be used in a wide temperature range can beprovided. In addition, when a rubber material is used, high chemicalresistance or high weather resistance can be achieved.

As a rubber material, typically, a material such as silicone rubber orfluorine rubber can be used. Silicone rubber or fluorine rubber can bemolded easily and favorably used for a product touching a human body.

As other rubber materials, materials such as natural rubber,styrene-butadiene rubber, isoprene rubber, butadiene rubber, chloroprenerubber, acrylonitrile-butadiene rubber, butyl rubber, urethane rubber,ethylene-propylene rubber, and ethylene-propylene-diene rubber can beused.

As a resin material, a thermoplastic elastomer having rubber elasticityat room temperature can be favorably used. When a thermoplasticelastomer is used, the number of steps for molding can be reduced ascompared with the case of using rubber which needs vulcanization. Forexample, a styrene-based elastomer, an olefin-based elastomer, anester-based elastomer, an amide-based elastomer, PVC (polyvinylchloride)-based elastomer, a urethane-based elastomer, a fluorine-basedelastomer, or the like can be used.

FIG. 1B is a schematic cross-sectional view of the first portion 21formed in the above manner, and FIG. 2A is a schematic perspective viewthereof. The first portion 21 has a belt-like shape. In the firstportion 21, a depression 23 having an opening edge 24 is formed on theshort side. The shape of the depression 23 is designed so that thebattery 30 described later fits into the depression 23.

The first portion 21 is formed using the mold 50 a illustrated in FIG.1A and has a shape in which the vicinity of the opening edge 24 is cutout obliquely as illustrated in FIG. 1B and FIG. 2A. Thus, the area ofthe opening edge 24 can be made large, so that the battery 30 isinserted easily as described below. In addition, the area where thesecond portion 22 of the exterior body 20 in the battery module 10described later and the first portion 21 are bonded to each other isincreased, so that the bonding strength can be enhanced (FIG. 1E andFIG. 2C).

Next, the battery 30 is inserted into the depression 23 from the openingedge 24 side of the first portion 21 (FIG. 1C and FIG. 2B).

The battery 30 includes an exterior body 31 and a pair of tabs 32. Here,an example of the case of using a film-like material for the exteriorbody 31 is described. A positive electrode, a negative electrode, and anelectrolyte are sealed in the exterior body 31. The pair of tabs 32 areelectrically connected to the positive electrode and the negativeelectrode and provided so as to project outside the exterior body 31.The exterior body 31 has a structure in which its side opposite to theside provided with the tabs 32 (also referred to as a bottom portion) isbent and three sides are bonded (sealed). Here, in some cases, among thesealed three sides of the exterior body 31, the side on the tabs 32 sideis referred to as a top sealing portion, and the other two sides areeach referred to as a side sealing portion. Note that in FIG. 1C and thelike, the internal structure of the battery 30 is not illustrated.

The battery 30 is provided so that at least part of the tabs 32 overlapswith the opening edge 24 and the other part of the tabs 32 projectsoutside the opening edge 24. The battery 30 may be provided so that anend portion of the exterior body 31 on the tab 32 side (the top sealingportion) is positioned at the opening edge 24.

As illustrated in FIG. 1C, when the battery 30 is inserted into thefirst portion 21, a space may be provided between the first portion 21and a bottom portion of the battery 30. Note that in the case where thebattery 30 is provided so as to pass through the neutral plane of theexterior body 31, for example, the space is not necessarily provided andthe battery 30 may be provided so that the first portion 21 and thebottom portion of the battery 30 are in contact with each other.

Next, as illustrated in FIG. 1D, the battery 30 and the first portion 21are provided in the mold 50 b for molding the second portion 22.

The mold 50 b includes an upper mold 52 a, a lower mold 52 b, and thelike. FIG. 1D illustrates an example in which the cores 54 a and 54 bare used. The upper mold 52 a includes an injection hole 55 b. Inaddition, the upper mold 52 a or the lower mold 52 b includes a venthole (not illustrated).

The injection hole 55 b of the mold 50 b is provided only in thevicinity of the opening edge 24 of the first portion 21. Thus, amaterial to be mold is injected only into the vicinity of the openingedge 24. Accordingly, in the second molding, a pressure in the moldingis applied only to part of the battery 30 which is in the vicinity ofthe opening edge 24 (the tabs 32, the top sealing portion of theexterior body 31, and the like), and not applied to the other part.Therefore, the exterior body 31 of the battery 30 can be prevented fromchanging its shape and being damaged. Because the tabs 32 and the topsealing portion of the exterior body 31 have a small thickness and donot have a hollow structure, a small change in the shape might occur dueto application of a pressure in the molding. However, there is nopossibility that damage occurs.

When the material is molded using the mold 50 b illustrated in FIG. 1D,the second portion 22 can be formed in contact with the first portion21. Thus, the exterior body 20 including the first portion 21 and thesecond portion 22 can be formed.

The method for molding the first portion 21 can be referred to for amethod for molding the second portion 22. It is preferable that thesecond portion 22 be formed by the method for forming the first portion21, in which case a facility can be shared.

Furthermore, it is preferable that the second portion 22 be molded usingthe same material as the first portion 21. This is because the adhesionbetween the first portion 21 and the second portion 22 can be increased.

Note that the first portion 21 and the second portion 22 may be moldedusing different materials and different molding methods. For example,the first portion 21 is formed using a millable thermosetting rubbermaterial by transfer molding to have high weather resistance and highchemical resistance. Then, the second portion 22 is molded using aliquid thermoplastic elastomer by injection molding and thus formed witha low pressure. In that case, damage to the battery 30 in molding thesecond portion 22 can be reduced more effectively.

The above is the description of a manufacturing method example.

FIG. 1E and FIG. 2C illustrate the battery module 10. The battery module10 includes the exterior body 20 and the battery 30.

The second portion 22 is bonded directly to the first portion 21. Thesecond portion 22 is provided so as to fill the opening edge 24 includedin the first portion 21. Thus, a space 25 surrounded by the firstportion 21 and the second portion 22 is formed in the exterior body 20.Part of the battery 30 is positioned in the space 25.

Part of the tabs 32 in the battery 30 projects from the second portion22 and is exposed to the outside. The tabs 32 can be electricallyconnected to a circuit board, terminals of an electronic device to whichthe battery module 10 is to be connected, or the like.

In the battery 30, the other part of the tabs 32 and the top sealingportion of the exterior body 31 are provided in contact with the secondportion 22. Accordingly, the battery 30 is fixed to the exterior body 20by the second portion 22. The other part of the exterior body 31 is notbonded to the first portion 21. Therefore, for example, when the firstportion 21 changes its shape, for example, is bent, the exterior body 31of the battery 30 and the first portion 21 can change their shapesindependently from each other, and thus they can be bent by weakerforce.

Here, an example in which the exterior body 20 of the battery module 10includes a hole 26 a and a hole 26 b each penetrating in the widthdirection is described. The hole 26 a provided on the tab 32 side isprovided for connection to a housing (a case) of an electronic deviceusing a spring bar or the like. The hole 26 b is provided for attachmentof a buckle or the like.

The exterior body 20 has a feature that the first portion 21 formedfirst is larger than the second portion 22 formed later. Specifically,the volume or the surface area of the second portion 22 is smaller thanthat of the first portion 21. It can also be said that at least one ofthe width, the length, and the thickness of the second portion 22 whenseen from the top surface or the side surface is smaller than that ofthe first portion 21. When the second portion 22 is formed smaller, theload on the battery 30 in forming the second portion 22 can be reduced.

The above is the description of Structure Example 1.

MODIFICATION EXAMPLE 1

FIGS. 3A to 3D are schematic cross-sectional views at respective stagesin a manufacturing method example described here. The method exemplifiedhere differs from the above manufacturing method example in that a mold50 c and a mold 50 d having different shapes are used.

In the above manufacturing method example, as illustrated in FIG. 1B andFIG. 2A, the first portion 21 has a shape such that the vicinity of theopening edge 24 is cut out obliquely. In contrast, in the mold 50 cillustrated in FIG. 3A, a space (a cavity) into which a material to bemolded is injected is formed in the mold 50 c so that a portion otherthan a portion into which a core 53 is inserted is formed.

First, the first portion 21 is formed using the mold 50 c by the moldingmethod exemplified in the above manufacturing method example.

FIG. 3B is a schematic cross-sectional view of the first portion 21molded using the mold 50 c. The opening edge 24 of the first portion 21is positioned on a side surface of the first portion 21.

Next, as illustrated in FIG. 3C, the battery 30 is inserted into thedepression 23 of the first portion 21 from the opening edge 24 side.FIG. 3C illustrates an example of the case where the battery 30 isinserted so that an end portion of the battery 30 which is on a sideopposite to the tab 32 side is in contact with a surface of thedepression 23 of the first portion 21.

Next, as illustrated in FIG. 3D, the first portion 21 into which thebattery 30 is inserted is provided in the mold 50 d.

The mold 50 d differs from the mold 50 b in the shape of part of theupper mold 52 a and the lower mold 52 b and the position of theinjection hole 55 b. The mold 50 d is processed so that a material to bemolded is injected on the opening edge 24 side positioned at the endportion of the first portion 21.

Next, the second portion 22 is formed using the mold 50 d by the moldingmethod exemplified in the above manufacturing method example.

When the second portion 22 is formed by the manufacturing method exampledescribed here, in the second molding, the area where the battery 30 andthe material to be molded are in contact with each other can be madesmall. Thus, a pressure and the like applied to the battery 30 in thesecond molding can be reduced, leading to formation with high yield.

The battery module 10 manufactured in the above-mentioned method isillustrated in FIG. 3E. Although the battery module 10 illustrated inFIG. 3E has the same external shape as that illustrated in FIG. 1E andFIG. 2C, the battery module 10 illustrated in FIG. 3E differs from thatillustrated in FIG. 1E and FIG. 2C in the shape of the second portion22. The battery module 10 illustrated in FIG. 3E can be distinguishedfrom that illustrated in FIG. 1E and FIG. 2C by a difference in theshape of the boundary (the parting line) formed on a surface of thebattery module 10. In an example illustrated in FIG. 3E, the boundarybetween the first portion 21 and the second portion 22 is positionedonly at an end portion of the battery module 10 on the attachment sideand thus is less likely to be viewed by a user when connection to anelectronic device is performed, so that a secondary effect such as ahigh design property can also be obtained.

The above is the description of Modification Example 1.

MODIFICATION EXAMPLE 2

Although the case of using the projecting part of the tabs 32 includedin the battery 30 as the electrodes of the battery module 10 isdescribed in the above structure example, another structure may beemployed.

FIGS. 4A and 4B illustrate an example of the case where the battery 30includes a circuit board 33. FIG. 4A is a schematic perspective view ofthe battery 30, and FIG. 4B is an enlarged schematic perspective viewwhen the battery 30 in FIG. 4A is seen from the rear side.

The battery 30 includes the circuit board 33 and a flexible printedcircuit (FPC) 34. The circuit board 33 is provided to overlap with thetop sealing portion of the exterior body 31.

The circuit board 33 can include a protection circuit, for example. Asthe protection circuit, a circuit having a function of stopping chargingin the case where the battery 30 is over charged, a function of stoppingdischarging in the case where the battery 30 is over discharged, or thelike can be used, for example. In addition, the protection circuitpreferably has a function of preventing a high current flow in the casewhere the positive electrode and the negative electrode are electricallyshorted. The protection circuit may have a function of outputting dataof the temperature of a cell in the battery 30 or a function of stoppingdischarging or charging in accordance with the temperature.

The circuit board 33 may include a protection circuit which detectsleakage from the battery 30. For example, it is possible to use acircuit having a structure in which a plurality of wirings which areapart from each other and electrically insulated from each other areprovided along the surface of the exterior body 31 and having a functionof detecting an electrical short-circuit when an electrolytic solutiontouches two wirings.

As the circuit board 33, a printed circuit board (PCB), an FPC, or thelike can be used. An IC chip including the protection circuit or thelike can be mounted on the circuit board 33.

The pair of tabs 32 are bent and bonded to terminals included in thecircuit board 33. An FPC 34 is connected to the circuit board 33. TheFPC 34 is electrically connected to a terminal for the positiveelectrode, a terminal for the negative electrode, a terminal foroutputting data of temperature, and the like, which are included in thecircuit board 33. The FPC 34 can be connected to a connector or the likeincluded in an electronic device.

FIG. 4C is a schematic perspective view of the battery module 10including the battery 30 illustrated in FIG. 4A. As illustrated in FIG.4C, the battery 30 is provided so that part of the FPC 34 is provided toproject from the second portion 22 of the exterior body 20.

The above is the description of Modification Example 2.

MODIFICATION EXAMPLE 3

When the exterior body 20 has a band-like shape as exemplified above,part of the exterior body 20 which is provided with the battery 30 isthinner than the other part thereof in some cases. In the case wheregreat force is locally applied in a direction perpendicular to a surfaceof the exterior body 20 from the outside, there is a possibility thatthe battery 30 changes its shape or is damaged. Accordingly, aprotection member for protecting a surface of the battery 30 ispreferably provided inside the exterior body 20.

FIG. 5A illustrates an example of a protection member 35. The protectionmember 35 has a shape in which a plate portion 35 a and a plate portion35 b facing each other are bonded with a bonding portion 35 c. The twoplate portions are provided substantially parallel to be apart from eachother so that a space into which the battery 30 is inserted is formed.The plate portions 35 a and 35 b are bonded to each other with thebonding portion 35 c at one short side included in each of the plateportions 35 a and 35 b.

FIG. 5B illustrates the case where the battery 30 is inserted into theprotection member 35. At this time, the battery 30 and the protectionmember 35 may be fixed or are not necessarily fixed. In the case wherethe battery 30 and the protection member 35 are fixed, they arepreferably fixed in the vicinity of the top sealing portion of thebattery 30 and the bonding portion 35 c of the protection member. Ineither case, the relative positions of the battery 30 and the protectionmember 35 are fixed by the second portion 22 of the exterior body 20when they are incorporated in the exterior body 20 of the battery module10.

As a material of the protection member 35, for example, metal, plastic,wood, or the like can be used. It is particularly preferable that theplate portions 35 a and 35 b be thin enough to have flexibility in thecase where the battery module 10 is bent and used. When the batterymodule 10 is bent and used, the thickness of the protection member 35is, for example, preferably greater than or equal to 0.02 mm and lessthan or equal to 2 mm, further preferably greater than or equal to 0.05mm and less than or equal to 1 mm, still further preferably greater thanor equal to 0.1 mm and less than or equal to 0.7 mm. Typically, it ispreferable that a metal plate having a thickness of 0.1 mm be used forthe plate portions 35 a and 35 b. With such a thickness, a user can wearthe battery module 10 without uncomfortable feeling. Note that in thecase where the battery module 10 is not used in a bent state, there isno limitation to the thickness, and the protection member 35 preferablyhas a larger thickness, in which case the strength can be increased.

With the protection member 35 described above, the battery 30 can beprotected from local pressure.

FIG. 6A1 is a schematic cross-sectional view of the battery module 10 towhich the protection member 35 is applied in a length direction. FIG.6A2 is a schematic cross-sectional view of the battery module 10 in awidth direction. FIGS. 6A1 and 6A2 each illustrate the plate portions 35a and 35 b of the protection member 35. As illustrated in FIGS. 6A1 and6A2, the battery 30 is provided in the exterior body 20 in a state wherethe battery 30 is interposed between the plate portions 35 a and 35 b.

FIG. 6A3 is an enlarged view of a region surrounded by a dashed line inFIG. 6A1. As illustrated in FIG. 6A3, end portions of the plate portions35 a and 35 b preferably project in the length direction so that theyare positioned outward from the exterior body 31 of the battery 30. Asillustrated in FIG. 6A2, the widths of the plate portions 35 a and 35 bare each preferably larger in the width direction than the width of thebattery 30 not including the widths of the side sealing portions. Inother words, the end portions of the plate portions 35 a and 35 b in thewidth direction preferably overlap with the side sealing portions of thebattery 30.

In the case where the battery module 10 is bent and used here, it ispreferable that part of the battery 30 and part of the plate portions 35a and 35 b other than those in the vicinity of the bonding portion 35 cnot be fixed. That is, the battery 30 and the plate portions 35 a and 35b preferably change their shapes independently from each other by beingshifted from each other when the battery module 10 is bent.

FIG. 6B1 is a schematic cross-sectional view of the battery module 10bent so that the plate portion 35 b lies on the inward side, and FIG.6B2 is an enlarged view of a region surrounded by a dashed line in FIG.6B1.

At this time, the battery 30 is provided so that the neutral plane ofthe first portion 21 of the exterior body 20 is positioned in asubstantially central portion of the battery 30. Therefore, the relativepositions of the end portion of the battery 30 and the first portion 21hardly change when the battery module 10 is bent. In contrast, the plateportion 35 a which lies on the outward side in the bending changes itsshape so that the end portion is apart from an inner wall of the firstportion 21. The plate portion 35 b which lies on the inward side in thebending changes its shape so that the end portion is closer to the innerwall of the first portion 21.

FIGS. 6C1 and 6C2 illustrate the case where bending is performed so thatthe plate portion 35 b lies on the outward side. At this time, the endportion of the plate portion 35 a slides closer to the inner wall of thefirst portion 21, and the end portion of the plate portion 35 b slidesapart from the inner wall of the first portion 21.

Thus, when the space is provided between the first portion 21 and theend portions of the plate portions 35 a and 35 b in a state where thebattery module 10 is not bent, the battery module 10 can be bent by weakforce without the first portion 21 and the end portion of the plateportions 35 a or 35 b being in contact with each other.

Here, when the lengths of the plate portions 35 a and 35 b are madedifferent, a function of preventing the battery module 10 from beingbent too much can be achieved.

FIGS. 7A1 and 7A2 illustrate an example of the case where the endportion of the plate portion 35 a is in contact with the inner wall ofthe first portion 21 of the exterior body 20 in a state where thebattery module 10 is unbent. The end portion of the plate portion 35 bis not in contact with the inner wall of the first portion 21, and thespace is provided therebetween.

In the case where bending is performed so that the plate portion 35 alies on the inward side as illustrated by an arrow in FIG. 7A1 here,there is no space to which the end portion of the plate portion 35 aslides outside, and thus the plate portion 35 a cannot be bent. As aresult, the plate portion 35 a serves as a stopper, and thus the batterymodule 10 cannot be bent.

In contrast, in the case where bending is performed so that the plateportion 35 a lies on the outward side, there is a space between the endportion of the plate portion 35 b and the inner wall of the firstportion 21, so that the battery module 10 can be bent.

FIGS. 7B1 and 7B2 each illustrate a cross section when bending isperformed so that the plate portion 35 b lies on the inward side. Atthis time, the end portion of the plate portion 35 a slides apart fromthe inner wall of the first portion 21, and the end portion of the plateportion 35 b slides closer to the inner wall.

FIGS. 7C1 and 7C2 each illustrate a cross section when bending isperformed with a larger curvature. At this time, when the end portion ofthe plate portion 35 b is in contact with the inner wall of the firstportion 21, for the same reason as described above, the plate portion 35b serves as a stopper, and thus the battery module 10 cannot be furtherbent.

When the shape of the space 25 and the lengths of the plate portions 35a and 35 b are changed in this manner, the movable range of the batterymodule 10 can be limited.

When the end portion of the plate portion 35 a (or the plate portion 35b) is in contact with the inner wall of the first portion 21 in bendingthe battery module 10, repulsion force is generated, and thus forcewhich is necessary for bending the battery module 10 becomes large ascompared with the case where the plate portion 35 (or the plate portion35 b) is not in contact with the inner wall of the exterior body 20.Accordingly, a user can notice the movable range of the battery module10, and thus the battery module 10 can be prevented from being bent toomuch unintentionally and damaged.

Note that when the lengths of the plate portions 35 a and 35 b are madeequal to each other, the allowable radius of curvature of the batterymodule 10 in the case where bending is performed so that the plateportion 35 a lies on the inward side can be substantially equal to thatin the case where bending is performed so that the plate portion 35 blies on the inward side. In contrast, when the plate portions 35 a and35 b have different lengths, the allowable radius of curvature can bemade different depending on the bending direction.

FIGS. 8A1, 8A2, and 8A3 illustrate an example of the case where a slit21 a, a slit 21 b, and a slit 21 c each serving as a guide are providedin the exterior body 20. With the slits 21 a, 21 b, and 21 c, shapesinto which the plate portions 35 a and 35 b change can be predeterminedwhen the exterior body 20 is bent.

The end portion of the plate portion 35 a is inserted into the slit 21a. The end portion of the plate portion 35 b is inserted into the slit21 b. Here, an example of the case where the plate portion 35 a islonger than the plate portion 35 b in the length direction so that theend portion of the plate portion 35 a is in contact with the inner wallof the slit 21 a is illustrated. Accordingly,

FIGS. 8A1 and 8A3 illustrate an example of the battery module 10designed so that the plate portion 35 a cannot be bent so as to lie onthe inward side.

When the battery module 10 is bent so that the plate portion 35 b lieson the inward side as illustrated in FIGS. 8B1 and 8B2, the plateportion 35 a can slide along the slit 21 a, and the plate portion 35 bcan slide along the slit 21 b.

When the battery module 10 is further bent as illustrated in FIGS. 8C1and 8C2, the end portion of the plate portion 35 b is in contact withthe inner wall of the slit 21 b, and thus the battery module 10 cannotbe further bent.

Thus, the slits 21 a and 21 b each serve as a guide for defining adirection in which the plate portions 35 a and 35 b slide. By provisionof the slits 21 a and 21 b, even when the battery module 10 is bent andunbent repeatedly, the end portions of the plate portions 35 a and 35 bcan be prevented from changing their shapes, so that the battery module10 can have high reliability.

Here, the lengths of the slits 21 a and 21 b and the lengths of theplate portions 35 a and 35 b can be set in accordance with the movablerange of the battery module 10. Although the lengths of the slits 21 aand 21 b are substantially equal to each other here, they may bedifferent from each other.

Although the battery module 10 has a structure in which the end portionof the plate portion 35 a is in contact with the inner wall of the slit21 a in a state where the battery module 10 is not bent (FIG. 8A1), thebattery module 10 may be bent so that the plate portion 35 a lies on theinward side by provision of a space between the end portion of the plateportion 35 a and the inner wall of the slit 21 a.

The lengths of the plate portion 35 a and the slit 21 a are preferablyset so that the end portion of the plate portion 35 a is positioned inthe slit 21 a when the end portion of the plate portion 35 a slidesinnermostly (on the second portion 22 side) as illustrated in FIG. 8C2.Similarly, the lengths of the plate portion 35 b and the slit 21 b arepreferably set so that the end portion of the plate portion 35 b ispositioned in the slit 21 b when the end portion of the plate portion 35b slides innermostly (on the second portion 22 side) as illustrated inFIG. 8A3.

FIG. 8A2 is a schematic cross-sectional view in the width direction.FIG. 8A2 illustrates an example in which the widths of the plateportions 35 a and 35 b are each larger in the width direction than thewidth of the battery 30 including the widths of the side sealingportions. The exterior body 20 is provided with the slits 21 c intowhich the end portions of the plate portions 35 a and 35 b in the widthdirection are inserted. With such a structure, the plate portions 35 aand 35 b are less likely to be shifted with respect to the exterior body20 in the width direction. Accordingly, the exterior body 20 and theplate portions 35 a and 35 b are more integrated in bending the batterymodule 10, so that a user can wear the battery module 10 withoutuncomfortable feeling.

The above is the description of Modification Example 3.

STRUCTURE EXAMPLE 2

An example of a battery module including a frame to which an electronicdevice can be attached is described below.

FIG. 9A illustrates a battery module 60 to which an electronic device 80is attached. The battery module 60 can also be used as a wearing tool ofthe electronic device 80. Accordingly, a device in which the electronicdevice 80 and the battery module 60 are combined can be used as awatch-type terminal device, for example. The electronic device 80 can beattached to and detached from the battery module 60 on the rear side.

FIG. 9B illustrates the battery module 60 from which the electronicdevice 80 is detached and FIG. 9C illustrates the electronic device 80.

The battery module 60 includes a band portion 61, a band portion 62, anda holding portion 63. The battery 30 is included in the band portion 61.The holding portion 63 is a portion for holding the electronic device80. The holding portion 63 includes a frame 70. In addition, the holdingportion 63 includes an operation button 64.

The electronic device 80 includes a housing 81. The housing 81 includesa display portion 82, a terminal 83, and a terminal 84.

In the battery module 60, an elastic body such as rubber is used for theband portion 61, the band portion 62, and the holding portion 63. Theband portion 61 and the band portion 62 are bonded directly to theholding portion 63, so that it can be said that they are integrated witheach other. In the holding portion 63, an elastic body such as rubber isdirectly formed so as to cover part of the frame 70. Accordingly, anadhesive or the like is not used for bonding the frame 70 and anexterior body covering the frame 70, and thus the bonding strength isincreased.

FIG. 10A illustrates the electronic device 80 when seen from the side ofthe terminals 83 and 84. FIG. 10B illustrates the frame 70 to which thebattery 30 is connected. FIG. 10C illustrates the frame 70 in FIG. 10Bwhich is rotated 180 degrees.

The frame 70 has a frame-like shape into which the electronic device 80fits. An inner surface of the frame 70 is provided with three terminals71 and a terminal 72.

The housing 81 of the electronic device 80 is provided with the threeterminals 83 and the terminal 84. The three terminals 71 provided on theinner surface of the frame 70 are provided at a position where the threeterminals 71 are in contact with the terminals 83 when the electronicdevice 80 is attached. Similarly, the terminal 72 is provided at aposition where the terminal 72 is in contact with the terminal 84.

A case 75 is attached to an outer surface of the frame 70. The tabs 32of the battery 30 are bonded to a pair of terminal portions included inthe case 75. The circuit board 33 (not illustrated) exemplified inModification Example 2 above is provided in the case 75. The threeterminals 71 provided for the frame 70 are electrically connected to aterminal for a positive electrode, a terminal for a negative electrode,and a terminal for outputting data of temperature of the circuit board33 (not illustrated).

The terminal 72 is a portion where the operation button 64 provided forthe holding portion 63 illustrated in FIG. 9B is connected to theterminal 84 included in the electronic device 80. The terminal 84 may bea physical button or an electrode. In the case where the terminal 84 isa physical button, the terminal 72 is formed using a movable member, andthe terminal 84 may be pushed with the terminal 72 interposedtherebetween when the operation button 64 is pushed, for example. Whenthe terminal 84 is an electrode, the terminal 72 may be an electricalswitch, and when the operation button 64 is pushed, for example, theterminal 72 may have a function of transmitting an electric signalshowing conduction or non-conduction to the terminal 84.

For the frame 70, a material which can withstand molding of an exteriorbody can be used. For example, any of a variety of materials such asplastic, metal, an alloy, glass, and wood can be used. It is preferableto use, for the frame 70, a material having higher rigidity than atleast the materials for the exterior body covering the frame 70, theband portion 61, and the band portion 62.

By the electronic device 80 being attached, such a battery module 60 canbe used as a main power supply or an auxiliary power supply of theelectronic device 80. The battery module 60 includes the frame 70 to andfrom which the electronic device 80 can be attached and detached easilyand thus can be replaced freely by a user as appropriate.

Note that although not illustrated, the battery module 60 preferablyincludes a power receiving unit such as a terminal for power receivingor an antenna capable of receiving power wirelessly. In the case wherethe electronic device 80 has a function of receiving power, the battery30 may be charged by transmission of power received by the electronicdevice 80 to the battery 30 through the terminals 71.

Next, an example of a method for manufacturing the battery module 60 isdescribed with reference to FIGS. 11A to 11C.

First, first molding using the first mold is performed, so that a firstportion 41 a is formed (FIG. 11A). The first portion 41 a is a portionto be the band portion 61 later. The above method can be referred to forthe molding method.

Furthermore, a first portion 41 b is separately formed. The firstportion 41 b is a portion to be the band portion 62 later. Note that thefirst portion 41 a and the first portion 41 b may be formed at the sametime using one mold.

Note that the battery 30 is not inserted on the first portion 41 b side,and therefore, the band portion 62 and the holding portion 63 may beformed at the same time by formation of the first portion 41 b in secondmolding described later.

Here, as illustrated in FIG. 11A, the depression 23 into which thebattery 30 is inserted is formed in the first portion 41 a. It ispreferable that part of the first portion 41 a and part of the firstportion 41 b each have a shape to be fitted to the frame 70.

Next, the battery 30 bonded to the frame 70 is inserted into the firstportion 41 a (FIG. 11B).

Next, the first portion 41 a, the first portion 41 b, and the frame 70are provided in the second mold, and second molding is performed, sothat a second portion 42 is molded (FIG. 11C). The second portion 42 isformed in contact with part of the first portion 41 a, part of the firstportion 41 b, and part of the frame 70. The second portion 42 is formedso as to fill a space between the first portion 41 a and the frame 70and a space between the first portion 41 b and the frame 70.Furthermore, the second portion 42 is formed so as to fill an opening ofthe depression 23 in the first portion 41 a.

By the above method, the battery module 60 can be manufactured. Sincethe battery module 60 is integrated with an elastic exterior body, highimpact resistance and a high design property can be obtained.

The above is the description of Structure Example 2.

STRUCTURE EXAMPLE 3

In the case of using a conventional hard exterior body such as metal,there is a possibility of a change in shape or damage in dropping,collision, or the like. In particular, for portable electronic devices,such risk is higher. In contrast, according to one embodiment of thepresent invention, since the exterior body including an elastic body canbe formed so as to cover the battery, high impact resistance can beobtained. Accordingly, the battery module of one embodiment of thepresent invention has a structure capable of being replaced with theconventional battery module, whereby an electronic device using thebattery module can have extremely high reliability.

A method for manufacturing the battery module which can be favorablyused for a portable electronic device is described below.

First, a battery 30 a is prepared. Here, an example of using a woundbattery as the battery 30 a is described. The battery 30 a includes theexterior body 31 and the pair of tabs 32.

Next, a case 91 is bonded to the tabs 32 of the battery 30 a (FIG. 12A).

FIG. 12B is an exploded view of the case 91. The case 91 includes a topcover 91 a, a bottom cover 91 b, and the circuit board 33 providedtherebetween. The bottom cover 91 b includes terminals to be bonded tothe tabs 32 of the battery 30 a and terminals to be connected to thecircuit board 33. The circuit board 33 includes three terminals 92. Thetop cover 91 a has openings at positions overlapping with the terminals92. Thus, the terminals 92 of the circuit board 33 are exposed.

Next, the first molding using the first mold is performed, so that afirst portion 95 is formed (FIG. 12C). The above method can be referredto for the molding method. A depression 94 into which the battery 30 acan be inserted is formed in the first portion 95.

Next, the battery 30 a is inserted into the depression 94 of the firstportion 95 (FIG. 12D).

Next, the first portion 95, the battery 30 a, and the case 91 areprovided in the second mold, and the second molding is performed, sothat a second portion 96 is molded (FIG. 12E). The second portion 96 isformed so as to fill an opening edge of the first portion 95.Furthermore, the second portion 96 is formed so as to fill a spacebetween the first portion 95 and the case 91. In addition, it ispreferable that the second portion 96 be formed so as to cover thebottom cover 91 b of the case 91. The second portion 96 may be formed soas to cover part of the top cover 91 a of the case 91. The top cover 91a serves as part of an exterior body of a battery module 90.

By the above method, the battery module 90 can be manufactured. Since anexterior body 97 of the battery module 90 is formed using an elasticbody, extremely high impact resistance can be obtained as compared withthe conventional battery module. Furthermore, in the battery module 90,the case 91 and the exterior body 97 are integrated with each other, andthus there is no space therebetween, so that entry of dust, water, andthe like is not caused, so that the battery module 90 has highreliability.

The above is the description of Structure Example 3.

APPLICATION EXAMPLE

The method for molding an exterior body which is one embodiment of thepresent invention can be applied not only to a battery module includinga battery but also to a module incorporating a variety of electroniccomponents. Thus, a module with high impact resistance can be obtained.

As an electronic component, for example, an electronic componentincluding at least an exterior body and an electrode can be used. Theabove structure examples of the battery module and the abovemanufacturing method examples can be referred to for a structure of amodule including an electronic component and a manufacturing methodthereof, and the battery may be replaced with such an electroniccomponent.

By any of the above methods for molding an exterior body, a variety ofmodules in each of which an electronic component having low resistanceto pressure or high temperature is covered with an exterior body such asrubber and a terminal is exposed can be manufactured. As an electroniccomponent, an IC chip such as a CPU, an FPGA, or a memory having avariety of functions, or an IC chip including a variety of sensors andthe like can also be used, for example.

As a sensor, an acceleration sensor, an angular velocity sensor, avibration sensor, a pressure sensor, a gyroscope sensor, an opticalsensor, or the like can be given. A sensor obtaining biologicalinformation of body temperature, blood pressure, pulse rate, the amountof sweat, lung capacity, blood sugar level, blood alcohol concentration,SpO₂ (blood oxygen saturation), fingerprints, veins, iris, voice prints,or the like can also be applied. Besides, any of a variety of sensorswhich measure force, displacement, position, speed, acceleration,angular velocity, rotational frequency, distance, light, liquid,magnetism, temperature, a chemical substance, a sound, time, hardness,electric field, current, voltage, electric power, radiation, flow rate,humidity, gradient, vibration, smell, and infrared rays can be used.

When a light-transmitting material is used for an exterior body,application to a display device or the like such as a liquid crystalpanel or an organic EL panel is possible. For example, a flexibledisplay panel can be covered with a light-transmitting rubber or thelike.

That is, one embodiment of the present invention is a module including afirst exterior body and an electronic component. The electroniccomponent includes a second exterior body and electrodes. The electrodesare provided so as to be exposed on a surface of the second exteriorbody. The first exterior body includes an elastic material. The firstexterior body includes a first portion, a second portion, and a spacesurrounded by the first portion and the second portion. The electroniccomponent is provided in the space, and the first portion and the secondportion are bonded to each other. The second portion is in contact withthe electrodes and the end portion of the second exterior body.

In the above, the first exterior body preferably includes a protectionmember. The protection member preferably includes a third portioncovering one of two surfaces of the second exterior body, which areopposite to each other, and a fourth portion covering the other. It ispreferable that the third portion and the fourth portion each have aplate-like shape and change its shape along the first exterior body.

Another embodiment of the present invention is a method formanufacturing a module including an electronic component and a firstexterior body covering the electronic component, which includes thefollowing steps. A first step is a step of preparing the electroniccomponent including a second exterior body and electrodes. A second stepis a step of forming a first portion including a depression by molding afirst material using a first mold. A third step is a step of insertingthe electronic component into the depression from the opening edge sideso that part of the electrodes projects outside the opening edge of thedepression. A fourth step is a step of forming the first exterior bodyin which the first portion and the second portion are bonded to eachother in such a manner that the second portion which seals the openingedge of the depression is formed by providing the first portion intowhich the electronic component is inserted in a second mold and moldinga second material using a second mold. The second portion is formed sothat it is in contact with the end portion of the second exterior bodyand part of the electrodes is exposed at the outside of the secondportion.

At least part of this embodiment can be implemented in combination withany of the other embodiments and an example described in thisspecification as appropriate.

Embodiment 2

Structure examples and manufacturing method examples of a secondarybattery that can be used in one embodiment of the present invention bedescribed below with reference to drawings. In particular, an example ofa bendable secondary battery will be described below.

STRUCTURE EXAMPLE

FIG. 13 is a perspective view showing an appearance of the secondarybattery 102. FIG. 14A is a cross-sectional view taken alongdashed-dotted line A1-A2 in FIG. 13 . FIG. 14B is a cross-sectional viewtaken along dashed-dotted line B1-B2 in FIG. 13 .

The secondary battery 102 of one embodiment of the present inventionincludes, in an exterior body 507, a positive electrode 511 covered witha separator 503, a negative electrode 515, and an electrolyte solution504. In the example in FIG. 13 and FIGS. 14A and 14B, the secondarybattery includes one positive electrode including a positive electrodeactive material layer 502 on one side of a positive electrode currentcollector 501, one positive electrode including the positive electrodeactive material layer 502 on each side of the positive electrode currentcollector 501, one negative electrode including a negative electrodeactive material layer 506 on one side of a negative electrode currentcollector 505, and one negative electrode including the negativeelectrode active material layer 506 on each side of the negativeelectrode current collector 505. The positive electrode 511 iselectrically connected to a positive electrode lead 521. The negativeelectrode 515 is electrically connected to a negative electrode lead525. Each of the positive electrode lead 521 and the negative electrodelead 525 is also referred to as a lead electrode or a lead terminal.Parts of the positive electrode lead 521 and the negative electrode lead525 are positioned outside the exterior body. The secondary battery 102is charged and discharged through the positive electrode lead 521 andthe negative electrode lead 525.

Note that although FIGS. 14A and 14B illustrate the example in which thepositive electrode 511 is covered with the separator 503, one embodimentof the present invention is not limited thereto. The positive electrode511 is not necessarily covered with the separator 503, for example. Thenegative electrode 515, instead of the positive electrode 511, may becovered with the separator 503, for example.

Positive Electrode

The positive electrode 511 includes, for example, the positive electrodecurrent collector 501 and the positive electrode active material layer502 formed over the positive electrode current collector 501. AlthoughFIGS. 14A and 14B illustrate the example of one positive electrode 511including the positive electrode active material layer 502 on only oneside of the positive electrode current collector 501 with a sheet shape(or a band-like shape) and one positive electrode 511 including thepositive electrode active material layer 502 on each side of thepositive electrode current collector 501, one embodiment of the presentinvention is not limited thereto. Only the positive electrodes 511 eachincluding the positive electrode active material layer 502 on only oneside of the positive electrode current collector 501 may be used. Onlythe positive electrodes 511 each including the positive electrode activematerial layer 502 on each side of the positive electrode currentcollector 501 may be used. The use of the positive electrodes 511including the positive electrode active material layer 502 on each sideof the positive electrode current collector 501 allows the secondarybattery 102 to have high capacity. In addition, the secondary battery102 may include three or more positive electrodes 511. An increase inthe number of the positive electrodes 511 in the secondary battery 102can increase the capacity of the secondary battery 102.

The positive electrode current collector 501 can be formed using amaterial that has high conductivity and does not dissolve at thepotential of the positive electrode, such as a metal typified bystainless steel, gold, platinum, aluminum, or titanium, or an alloythereof.

Alternatively, an aluminum alloy to which an element which improves heatresistance, such as silicon, titanium, neodymium, scandium, ormolybdenum, is added can be used. Still alternatively, a metal elementwhich forms silicide by reacting with silicon can be used. Examples ofthe metal element which forms silicide by reacting with silicon arezirconium, titanium, hafnium, vanadium, niobium, tantalum, chromium,molybdenum, tungsten, cobalt, nickel, and the like. The positiveelectrode current collector 501 can have a foil-like shape, a plate-likeshape (a sheet-like shape), a net-like shape, a punching-metal shape, anexpanded-metal shape, or the like as appropriate. The positive electrodecurrent collector 501 preferably has a thickness of greater than orequal to 5 μm and less than or equal to 30 μm. The surface of thepositive electrode current collector 501 may be provided with anundercoat layer using graphite or the like.

The positive electrode active material layer 502 may further include, inaddition to a positive electrode active material, a binder forincreasing adhesion of the positive electrode active material, aconductive additive for increasing the conductivity of the positiveelectrode active material layer 502, and the like.

Examples of the positive electrode active material that can be used forthe positive electrode active material layer 502 include a compositeoxide with an olivine crystal structure, a composite oxide with alayered rock-salt crystal structure, and a composite oxide with a spinelcrystal structure. For example, a compound such as LiFeO₂, LiCoO₂,LiNiO₂, LiMn₂O₄, V₂O₅, Cr₂O₅, or MnO₂ can be used as the positiveelectrode active material.

In particular, LiCoO₂ is preferable because it has high capacity andhigher stability in the air and higher thermal stability than LiNiO₂,for example.

It is preferable to add a small amount of lithium nickel oxide (LiNiO₂or LiNi_(1-x)M_(x)O₂ (0<x<1) (M=Co, Al, or the like)) to alithium-containing material with a spinel crystal structure whichcontains manganese such as LiMn₂O₄ because characteristics of thesecondary battery using such a material can be improved.

Alternatively, a complex material (LiMPO₄ (general formula) (M is one ormore of Fe(II), Mn(II), Co(II), and Ni(II))) can be used. Typicalexamples of the general formula LiMPO₄ which can be used as a materialare lithium compounds such as LiFePO₄, LiNiPO₄, LiCoPO₄, LiMnPO₄,LiFe_(a)Ni_(b)PO₄, LiFe_(a)Co_(b)PO₄, LiFe_(a)Mn_(b)PO₄,LiNi_(a)Co_(b)PO₄, LiNi_(a)Mn_(b)PO₄ (a+b≤1, 0<a<1, and 0<b<1),LiFe_(c)Ni_(d)Co_(e)PO₄, LiFe_(c)Ni_(d)Mn_(e)PO₄,LiNi_(c)Co_(d)Mn_(e)PO₄ (c+d+e≤1, 0<c<1, 0<d<1, and 0<e<1), andLiFe_(f)Ni_(g)Co_(h)Mn_(i)PO₄ (f+g+h+i≤1, 0<f<1, 0<g<1, 0<h<1, and0<i<1).

LiFePO₄ is particularly preferable because it meets requirements for thepositive electrode active material in a balanced manner, such as safety,stability, high capacity density, and the existence of lithium ions thatcan be extracted in initial oxidation (charging).

Alternatively, a complex material such as LiM_(((2-j))MSiO₄ (generalformula) (M is one or more of Fe(II), Mn(II), Co(II), and Ni(II); 0≤j≤2)can be used. Typical examples of the general formula Li_((2-j))MSiO₄which can be used as a material are lithium compounds such asLi_((2-j))FeSiO₄, Li_((2-j))NiSiO₄, Li_((2-j))CoSiO₄, Li_((2-j))MnSiO₄,Li_((2-j))Fe_(k)Ni_(l)SiO₄, Li_((2-j))Fe_(k)Co_(l)SiO₄,Li_((2-j))Fe_(k)Mn_(l)SiO₄, Li_((2-j))Ni_(k)Co_(l)SiO₄,Li_((2-j))Ni_(k)Mn_(l)SiO₄ (k+l≤1, 0<k<1, and 0<l<1),Li_((2-j))Fe_(m)Ni_(n)Co_(q)SiO_(v), Li_((2-j))Fe_(m)Ni_(n)Mn_(q)SiO₄,Li_((2-j))Ni_(m)Co_(n)Mn_(q)SiO₄ (m+n+q≤1, 0<m<1, 0<n<1, and 0<q<1), andLi_((2-j))Fe_(r)Ni_(s)Co_(t)Mn_(u)SiO₄ (r+s+t+u≤1, 0<r<1, 0<s<1, 0<t<1,and 0<u<1).

Still alternatively, a nasicon compound expressed by A_(x)M₂(XO₄)₃(general formula) (A=Li, Na, or Mg, M=Fe, Mn, Ti, V, or Nb, X=S, P, Mo,W, As, or Si) can be used for the positive electrode active material.Examples of the nasicon compound are Fe₂(MnO₄)₃, Fe₂(SO₄)₃, andLi₃Fe₂(PO₄)₃. Further alternatively, a compound expressed by Li₂MPO₄F,Li₂MP₂O₇, or Li₅MO₄ (general formula) (M=Fe or Mn), a perovskitefluoride such as NaFeF₃ and FeF₃, a metal chalcogenide (a sulfide, aselenide, or a telluride) such as TiS₂ and MoS₂, an oxide with aninverse spinel crystal structure such as LiMVO₄, a vanadium oxide (V₂O₅,V₆O₁₃, LiV₃O₈, or the like), a manganese oxide, an organic sulfurcompound, or the like can be used as the positive electrode activematerial.

In the case where carrier ions are alkali metal ions other than lithiumions, or alkaline-earth metal ions, a material containing an alkalimetal (e.g., sodium or potassium) or an alkaline-earth metal (e.g.,calcium, strontium, barium, beryllium, or magnesium) instead of lithiummay be used as the positive electrode active material. For example, thepositive electrode active material may be a layered oxide containingsodium such as NaFeO₂ or Na_(2/3)[Fe_(1/2)Mn_(1/2)]O₂.

Further alternatively, any of the above materials may be combined to beused as the positive electrode active material. For example, a solidsolution obtained by combining two or more of the above materials can beused as the positive electrode active material. For example, a solidsolution of LiCo_(1/3)Mn_(1/3)Ni_(1/3)O₂ and Li₂MnO₃ can be used as thepositive electrode active material.

Note that although not illustrated, a conductive material such as acarbon layer may be provided on a surface of the positive electrodeactive material layer 502. With the conductive material such as thecarbon layer, conductivity of the electrode can be increased. Forexample, the positive electrode active material layer 502 can be coatedwith the carbon layer by mixing a carbohydrate such as glucose at thetime of baking the positive electrode active material.

The average particle diameter of the primary particle of the positiveelectrode active material layer 502 is preferably greater than or equalto 50 nm and less than or equal to 100 μm.

Examples of the conductive additive include acetylene black (AB),graphite (black lead) particles, carbon nanotubes, graphene, andfullerene.

A network for electron conduction can be formed in the positiveelectrode 511 by the conductive additive. The conductive additive alsoallows maintaining of a path for electric conduction between theparticles of the positive electrode active material layer 502. Theaddition of the conductive additive to the positive electrode activematerial layer 502 increases the electron conductivity of the positiveelectrode active material layer 502.

As the binder, instead of polyvinylidene fluoride (PVDF) as a typicalone, polyimide, polytetrafluoroethylene, polyvinyl chloride,ethylene-propylene-diene polymer, styrene-butadiene rubber,acrylonitrile-butadiene rubber, fluorine rubber, polyvinyl acetate,polymethyl methacrylate, polyethylene, nitrocellulose or the like can beused.

A favorable range of the content of the binder in the positive electrodeactive material layer 502 may be determined as appropriate in accordancewith the particle diameter of the active material, and can be preferablygreater than or equal to 1 wt % and less than or equal to 10 wt %. Forexample, the favorable range can be greater than or equal to 2 wt % andless than or equal to 8 wt % or greater than or equal to 3 wt % and lessthan or equal to 5 wt %. The content of the conductive additive in thepositive electrode active material layer 502 is preferably greater thanor equal to 1 wt % and less than or equal to 10 wt %, further preferablygreater than or equal to 1 wt % and less than or equal to 5 wt %.

In the case where the positive electrode active material layer 502 isformed by a coating method, the positive electrode active material, thebinder, and the conductive additive are mixed to form a positiveelectrode paste (slurry), and the positive electrode paste is applied tothe positive electrode current collector 501 and dried.

Negative Electrode

The negative electrode 515 includes, for example, the negative electrodecurrent collector 505 and the negative electrode active material layer506 formed over the negative electrode current collector 505. AlthoughFIGS. 14A and 14B illustrate the example of one negative electrode 515including the negative electrode active material layer 506 on only oneside of the negative electrode current collector 505 with a sheet shape(or a band-like shape) and one negative electrode 515 including thenegative electrode active material layer 506 on each side of thenegative electrode current collector 505, one embodiment of the presentinvention is not limited thereto. Only the negative electrodes 515 eachincluding the negative electrode active material layer 506 on only oneside of the negative electrode current collector 505 may be used. Inthis case, the sides of the negative electrode current collectors 505,each of which is not provided with the negative electrode activematerial layer 506, are preferably placed to be in contact with eachother because such arrangement can make friction between the contactingsides low to easily relieve stress generated when the secondary battery102 is curved. Only the negative electrodes 515 each including thenegative electrode active material layer 506 on each side of thenegative electrode current collector 505 may be used. The use of thenegative electrode 515 including the negative electrode active materiallayer 506 on each side of the negative electrode current collector 505allows the secondary battery 102 to have high capacity. In addition, thesecondary battery 102 may include three or more negative electrodes 515.An increase in the number of the negative electrodes 515 in thesecondary battery 102 can increase the capacity of the secondary battery102.

The negative electrode current collector 505 can be formed using amaterial that has high conductivity and is not alloyed with a carrierion of lithium or the like, such as stainless steel, gold, platinum,iron, copper, titanium, or an alloy thereof. Alternatively, an aluminumalloy to which an element which improves heat resistance, such assilicon, titanium, neodymium, scandium, or molybdenum, is added can beused. The negative electrode current collector 505 can have a foil-likeshape, a plate-like shape (a sheet-like shape), a net-like shape, apunching-metal shape, an expanded-metal shape, or the like asappropriate. The negative electrode current collector 505 preferably hasa thickness greater than or equal to 5 μm and less than or equal to 30μm. The surface of the negative electrode current collector 505 may beprovided with an undercoat layer using graphite or the like.

The negative electrode active material layer 506 may further include, inaddition to a negative electrode active material, a binder forincreasing adhesion of the negative electrode active material, aconductive additive for increasing the conductivity of the negativeelectrode active material layer 506, and the like.

There is no particular limitation on the negative electrode activematerial as long as it is a material with which lithium can be dissolvedand precipitated or a material into/from which lithium ions can beinserted and extracted. Other than a lithium metal or lithium titanate,a carbon-based material generally used in the field of power storage, analloy-based material, or the like can also be used for the negativeelectrode active material layer 506.

The lithium metal is preferable because of its low redox potential(3.045 V lower than that of a standard hydrogen electrode) and highspecific capacity per unit weight and per unit volume (3860 mAh/g and2062 mAh/cm³).

Examples of the carbon-based material include graphite, graphitizingcarbon (soft carbon), non-graphitizing carbon (hard carbon), a carbonnanotube, graphene, carbon black, and the like.

Examples of the graphite include artificial graphite such as meso-carbonmicrobeads (MCMB), coke-based artificial graphite, or pitch-basedartificial graphite and natural graphite such as spherical naturalgraphite.

Graphite has a low potential substantially equal to that of a lithiummetal (0.1 V to 0.3 V vs. Li/Li⁺) when lithium ions are inserted intothe graphite (when a lithium-graphite intercalation compound is formed).For this reason, a lithium ion battery can have a high operatingvoltage. In addition, graphite is preferable because of its advantagessuch as relatively high capacity per unit volume, small volumeexpansion, low cost, and safety greater than that of a lithium metal.

For the negative electrode active material, an alloy-based material oran oxide which enables charge-discharge reaction by an alloying reactionand a dealloying reaction with lithium can be used. In the case wherelithium ions are carrier ions, the alloy-based material is, for example,a material containing at least one of Mg, Ca, Al, Si, Ge, Sn, Pb, Sb,Bi, Ag, Au, Zn, Cd, Hg, In, and the like. Such elements have highercapacity than carbon. In particular, silicon has a significantly hightheoretical capacity of 4200 mAh/g. For this reason, silicon ispreferably used as the negative electrode active material. Examples ofthe alloy-based material using such elements include Mg₂Si, Mg₂Ge,Mg₂Sn, SnS₂, V₂Sn₃, FeSn₂, CoSn₂, Ni₃Sn₂, Cu₆Sn₂, Ag₃Sn, Ag₃Sb, Ni₂MnSb,CeSb₃, LaSn₃, La₃Co₂Sn₇, CoSb₃, InSb, SbSn, and the like.

Alternatively, for the negative electrode active material, an oxide suchas SiO, SnO, SnO₂, titanium oxide (TiO₂), lithium titanium oxide(Li₄Ti₅O₁₂), lithium-graphite intercalation compound (Li_(x)C₆), niobiumoxide (Nb₂O₅), tungsten oxide (WO₂), or molybdenum oxide (MoO₂) can beused.

Still alternatively, for the negative electrode active material,Li_(3-x)M_(x)N (M is Co, Ni, or Cu) with a Li₃N structure, which is anitride containing lithium and a transition metal, can be used. Forexample, Li_(2.6)Co_(0.4)N₃ is preferable because of high charge anddischarge capacity (900 mAh/g and 1890 mAh/cm³).

A nitride containing lithium and a transition metal is preferably used,in which case lithium ions are contained in the negative electrodeactive materials and thus the negative electrode active materials can beused in combination with a material for a positive electrode activematerial that does not contain lithium ions, such as V₂O₅ or Cr₃O₈. Notethat in the case of using a material containing lithium ions as apositive electrode active material, the nitride containing lithium and atransition metal can be used as the negative electrode active materialby extracting the lithium ions contained in the positive electrodeactive material in advance.

Alternatively, a material which causes a conversion reaction can be usedas the negative electrode active material. For example, a transitionmetal oxide with which an alloying reaction with lithium is not caused,such as cobalt oxide (CoO), nickel oxide (NiO), or iron oxide (FeO), maybe used for the negative electrode active material. Other examples ofthe material which causes a conversion reaction include oxides such asFe₂O₃, CuO, Cu₂O, RuO₂, and Cr₂O₃, sulfides such as CoS_(0.89), NiS, orCuS, nitrides such as Zn₃N₂, Cu₃N, and Ge₃N₄, phosphides such as NiP₂,FeP₂, and CoP₃, and fluorides such as FeF₃ and BiF₃. Note that any ofthe fluorides can be used as a positive electrode active materialbecause of its high potential.

In the case where the negative electrode active material layer 506 isformed by a coating method, the negative electrode active material andthe binder are mixed to form a negative electrode paste (slurry), andthe negative electrode paste is applied to the negative electrodecurrent collector 505 and dried. Note that a conductive additive may beadded to the negative electrode paste.

Graphene may be formed on a surface of the negative electrode activematerial layer 506. In the case of using silicon as the negativeelectrode active material, the volume of silicon is greatly changed dueto occlusion and release of carrier ions in charge-discharge cycles.Therefore, adhesion between the negative electrode current collector 505and the negative electrode active material layer 506 is decreased,resulting in degradation of battery characteristics caused by charge anddischarge. Thus, graphene is preferably formed on a surface of thenegative electrode active material layer 506 containing silicon becauseeven when the volume of silicon is changed in charge-discharge cycles,decrease in the adhesion between the negative electrode currentcollector 505 and the negative electrode active material layer 506 canbe inhibited, which makes it possible to reduce degradation of batterycharacteristics.

Alternatively, a coating film of an oxide or the like may be formed onthe surface of the negative electrode active material layer 506. Acoating film formed by decomposition or the like of an electrolytesolution or the like in charging cannot release electric charges used atthe formation, and therefore forms irreversible capacity. In contrast,the film of an oxide or the like provided on the surface of the negativeelectrode active material layer 506 in advance can reduce or preventgeneration of irreversible capacity.

As the coating film coating the negative electrode active material layer506, an oxide film of any one of niobium, titanium, vanadium, tantalum,tungsten, zirconium, molybdenum, hafnium, chromium, aluminum, andsilicon or an oxide film containing any one of these elements andlithium can be used. Such a coating film is denser than a conventionalcoating film formed on a surface of a negative electrode due to adecomposition product of an electrolyte solution.

For example, niobium oxide (Nb₂O₅) has a low electric conductivity of10⁻⁹ S/cm and a high insulating property. For this reason, a niobiumoxide film inhibits electrochemical decomposition reaction between thenegative electrode active material and the electrolyte solution. On theother hand, niobium oxide has a lithium diffusion coefficient of 10⁻⁹cm²/sec and high lithium ion conductivity. Therefore, niobium oxide cantransmit lithium ions. Alternatively, silicon oxide or aluminum oxidemay be used.

A sol-gel method can be used to coat the negative electrode activematerial layer 506 with the coating film, for example. The sol-gelmethod is a method for forming a thin film in such a manner that asolution of metal alkoxide, a metal salt, or the like is changed into agel, which has lost its fluidity, by hydrolysis reaction andpolycondensation reaction and the gel is baked. Since a thin film isformed from a liquid phase in the sol-gel method, raw materials can bemixed uniformly on the molecular scale. For this reason, by adding anegative electrode active material such as graphite to a raw material ofthe metal oxide film which is a solvent, the active material can beeasily dispersed into the gel. In such a manner, the coating film can beformed on the surface of the negative electrode active material layer506. A decrease in the capacity of the power storage unit can beprevented by using the coating film.

Separator

As a material of the separator 503, a porous insulator such ascellulose, polypropylene (PP), polyethylene (PE), polybutene, nylon,polyester, polysulfone, polyacrylonitrile, polyvinylidene fluoride,tetrafluoroethylene, or polyphenylene sulfide can be used.Alternatively, nonwoven fabric of a glass fiber or the like, or adiaphragm in which a glass fiber and a polymer fiber are mixed may beused.

Electrolyte Solution

As an electrolyte in the electrolyte solution 504, a material havingcarrier ion mobility and containing lithium ions serving as carrier ionsis used. Typical examples of the electrolyte are lithium salts such asLiPF₆, LiClO₄, LiAsF₆, LiBF₄, LiCF₃SO₃, Li(CF₃SO₂)₂N, Li(C₂F₅SO₂)₂N, andLi(SO₂F)₂N. One of these electrolytes may be used alone, or two or moreof them may be used in an appropriate combination and in an appropriateratio.

It is particularly preferable that the electrolyte have high heatresistance in the case where treatment is performed at high temperaturein molding rubber or the like. It is preferable to use imide salt havinghigh thermal decomposition temperature, for example.

As a solvent of the electrolyte solution 504, a material having carrierion mobility is used. As the solvent of the electrolyte solution, anaprotic organic solvent is preferably used. Typical examples of aproticorganic solvents include ethylene carbonate (EC), propylene carbonate(PC), dimethyl carbonate, diethyl carbonate (DEC), ethylmethyl carbonate(EMC), γ-butyrolactone, acetonitrile, dimethoxyethane, tetrahydrofuran,and the like, and one or more of these materials can be used. When agelled high-molecular material is used as the solvent of theelectrolytic solution or a high-molecular material for gelling is addedto the electrolytic solution, for example, safety against liquid leakageand the like is improved. Furthermore, the secondary battery can bethinner and more lightweight. Typical examples of gelled high-molecularmaterials include a silicone gel, an acrylic gel, an acrylonitrile gel,a polyethylene oxide-based gel, a polypropylene oxide-based gel, a gelof a fluorine-based polymer, and the like. Alternatively, the use of oneor more kinds of ionic liquids (room temperature molten salts) whichhave features of non-flammability and non-volatility as the solvent ofthe electrolyte solution can prevent the secondary battery fromexploding or catching fire even when the secondary battery internallyshorts out or the internal temperature increases owing to overchargingor the like. An ionic liquid is a salt in the fluid state and has highion mobility (conductivity). An ionic liquid contains a cation and ananion. Examples of ionic liquids include an ionic liquid containing anethylmethylimidazolium (EMI) cation and an ionic liquid containing anN-methyl-N-propylpiperidinium (PP₁₃) cation.

It is particularly preferable to use a material having high boilingtemperature as the solvent of the electrolyte solution in the case wheretreatment is performed at high temperature in molding rubber or thelike. It is preferable to use propylene carbonate (PC), for example.

Exterior Body

There are a variety of structures of a secondary battery, and a film isused for formation of the exterior body 507 in this embodiment. Notethat the film used for the exterior body 507 is a single-layer filmselected from a metal film (e.g., an aluminum film, a stainless steelfilm, and a nickel steel film), a plastic film made of an organicmaterial, a hybrid material film including an organic material (e.g., anorganic resin or fiber) and an inorganic material (e.g., ceramic), and acarbon-containing inorganic film (e.g., a carbon film or a graphitefilm); or a stacked-layer film including two or more of the above films.Forming depressions or projections on a surface of a metal film byembossing increases the surface area of the exterior body 507 exposed tooutside air, achieving efficient heat dissipation.

In the case where the secondary battery 102 is changed in form byexternally applying force, bending stress is externally applied to theexterior body 507 of the secondary battery 102. This might partly deformor damage the exterior body 507. Projections or depressions formed onthe exterior body 507 can relieve a strain caused by stress applied tothe exterior body 507. Therefore, the secondary battery 102 can be morereliable. Note that a “strain” is the scale of change in form indicatingthe displacement of a point of an object relative to the reference(initial) length of the object. The exterior body 507 having depressionsor projections can reduce the influence of a strain caused byapplication of external force to the secondary battery to an acceptablelevel. Thus, the secondary battery having high reliability can beprovided.

The above is the description of the structure example.

FABRICATING METHOD EXAMPLE

An example of a fabricating method of the secondary battery 102 isdescribed below.

Preparing Positive Electrode and Covering it with Separator

First, the positive electrode 511 including the positive electrodeactive material layer 502 is placed on the separator 503 (see FIG. 15A).FIG. 15A illustrates an example where the positive electrode activematerial layer 502 is provided on each side of the positive electrodecurrent collector 501 having a meandering shape in which slits areformed.

The slit formed in the positive electrode current collectors 501 cansuppress the difference between the positions of end portions of theplurality of current collectors when the secondary battery 102 iscurved. The slit can also relieve tension applied to the currentcollector far from the curvature center.

Furthermore, there is no positive electrode active material layer 502 ina region 511 a, which overlaps with a slit of the negative electrode 515when the positive electrode 511 and the negative electrode 515 arestacked in a later step. If the positive electrode active material layer502 is present in the region 511 a, where the positive electrode 511overlaps with the slit of the negative electrode 515, there is nonegative electrode active material layer 506 in a region overlappingwith this positive electrode active material layer 502, which mightcause a problem in a battery reaction. Specifically, this mightconcentrate carrier ions released from the positive electrode activematerial layer 502 in the negative electrode active material layer 506in the region closest to the slit, so that the carrier ions might bedeposited on the negative electrode active material layer 506. Thus, thedeposition of the carrier ions on the negative electrode active materiallayer 506 can be suppressed when there is no positive electrode activematerial layer 502 in the region 511 a, which overlaps with the slit ofthe negative electrode 515.

Then, the separator 503 is folded along the dotted line in FIG. 15A sothat the positive electrode 511 is interposed between facing parts ofthe separator 503. Next, the outer edges of the separator 503, which isoutside of the positive electrode 511, are bonded to form the bag-likeseparator 503 (see FIG. 15B). The bonding of the outer edges of theseparator 503 can be performed with the use of an adhesive or the like,by ultrasonic welding, or by thermal fusion bonding.

In this embodiment, polypropylene is used as the separator 503, and theouter edges of the separator 503 are bonded to each other by heating.Bonding portions 503 a are illustrated in FIG. 15B. In such a manner,the positive electrode 511 can be covered with the separator 503. Theseparator 503 is formed so as to cover the positive electrode activematerial layer 502 and does not necessarily cover the whole positiveelectrode 511.

Note that although FIGS. 15A and 15B illustrate the example in which theseparator 503 is folded, one embodiment of the present invention is notlimited thereto. For example, the positive electrode 511 may beinterposed between two separators. In that case, the bonding portion 503a may be formed to surround almost all of the four sides of the positiveelectrode 511.

The outer edges of the separator 503 may be bonded intermittently or maybe bonded at dot-like bonding portions provided at regular intervals.

Alternatively, bonding may be performed along only one side of the outeredges. Alternatively, bonding may be performed along only two sides ofthe outer edges. Alternatively, bonding may be performed along foursides of the outer edges; accordingly, the four sides can be in an evenstate.

Note that although the case where the positive electrode 511 is coveredwith the separator 503 is shown in FIGS. 15A and 15B, and the like, oneembodiment of the present invention is not limited thereto. The positiveelectrode 511 is not necessarily covered with the separator 503, forexample. The negative electrode 515, instead of the positive electrode511, may be covered with the separator 503, for example.

Preparing Negative Electrode

Next, the negative electrode 515 is prepared (see FIG. 15C). FIG. 15Cillustrates an example where the negative electrode active materiallayer 506 is provided on each side of the negative electrode currentcollector 505 having a meandering shape in which slits are formed.

The slit formed in the negative electrode current collectors 505 cansuppress the difference between the positions of end portions of theplurality of current collectors when the secondary battery 102 iscurved. The slit can also relieve tension applied to the currentcollector far from the curvature center.

Making Positive Electrodes and Negative Electrodes Overlap with EachOther and Connecting Leads

Next, the positive electrodes 511 and the negative electrodes 515 arestacked (see FIG. 16A). This embodiment shows an example in which twopositive electrodes 511 and two negative electrodes 515 are used.

Next, the positive electrode lead 521 including a sealing layer 520 iselectrically connected to positive electrode tabs of the plurality ofpositive electrode current collectors 501 by ultrasonic wave irradiationwith pressure applied (ultrasonic welding). Alternatively, welding usinga laser may be performed.

The lead is likely to be cracked or cut by stress due to external forceapplied after fabrication of the secondary battery 102.

When the positive electrode lead 521 is subjected to ultrasonic welding,a connection region and a curved portion can be formed in the positiveelectrode tab (FIG. 16B).

This curved portion can relieve stress due to external force appliedafter fabrication of the secondary battery 102. Therefore, the secondarybattery 102 can be more reliable.

The curved portion is not necessarily formed in the positive electrodetab. The positive electrode current collector may be formed using ahigh-strength material such as stainless steel to a thickness of 10 μmor less, in order to easily relieve stress due to external force appliedafter fabrication of a secondary battery.

It is needless to say that two or more of the above examples may becombined to relieve concentration of stress in the positive electrodetab.

Then, in a manner similar to that of the positive electrode currentcollector 501, the negative electrode lead 525 including the sealinglayer 520 is electrically connected to the negative electrode tab of thenegative electrode current collector 505 by ultrasonic welding.

Preparing Exterior Body and Covering Positive Electrodes and NegativeElectrodes

A film used as an exterior body is folded, and thermocompression bondingis performed along one side of the folded exterior body. A portion wherethermocompression bonding is performed along one side of the foldedexterior body 507 is shown as a bonding portion 507 a in FIG. 16B. Withthe exterior body 507 thus obtained, the positive electrodes 511 and thenegative electrodes 515 are covered.

Injecting Electrolyte Solution

Next, thermocompression bonding is also performed in a manner similar tothe above along one side of the exterior body 507, which overlaps withthe sealing layer 520 provided on the positive electrode lead 521 andthe sealing layer 520 provided on the negative electrode lead 525 (FIG.17A). After that, the electrolyte solution 504 is injected from anunsealed side 507 b of the exterior body 507, which is illustrated inFIG. 17A, into a region covered with the exterior body 507.

Then, the remaining open side (the side 507 b) of the exterior body 507is sealed under vacuum, heating, and pressing, whereby the secondarybattery 102 can be formed (FIG. 17B). Injecting the electrolyte solutionand sealing are performed in an environment from which an impurity suchas oxygen, water, or nitrogen is eliminated, for example, in a glovebox. The evacuation to a vacuum is preferably performed with a vacuumsealer, a liquid pouring sealer, or the like. Heating and pressing canbe performed for the unsealed side 507 b placed between two heatablebars included in the sealer. An example of the conditions is as follows:the degree of vacuum is 40 kPa, the heating temperature is 190° C., thepressure is 0.1 MPa, and the time is 3 seconds. Here, the side 507 b maybe sealed while pressing part of the exterior body 507 where a positiveelectrode and a negative electrode are positioned. By the pressureapplication, bubbles which enter between the positive electrode and thenegative electrode when the electrolyte solution is injected can beremoved.

MODIFICATION EXAMPLE

FIG. 18A illustrates a modification example of the secondary battery102. The secondary battery 102 illustrated in FIG. 18A is different fromthe secondary battery 102 shown in FIGS. 16A and 16B in the arrangementof the positive electrode lead 521 and the negative electrode lead 525.Specifically, the positive electrode lead 521 and the negative electrodelead 525 in the secondary battery 102 in FIGS. 16A and 16B are providedon the same side of the exterior body 507, whereas the positiveelectrode lead 521 and the negative electrode lead 525 in the secondarybattery 102 in FIGS. 18A and 18B are provided on different sides of theexterior body 507. Thus, the leads of the secondary battery of oneembodiment of the present invention can be freely positioned, andaccordingly the degree of freedom in design is high. Accordingly, aproduct including the secondary battery of one embodiment of the presentinvention can have a higher degree of freedom in design. Furthermore,the yield of products each including the secondary battery of oneembodiment of the present invention can be increased.

FIG. 18B illustrates a fabrication process of the secondary battery 102in FIG. 18A. The fabricating method of the secondary battery 102 in FIG.13 can be referred to for the details. Note that in FIG. 18B, theelectrolyte solution 504 is not illustrated.

Pressing (e.g., embossing) may be performed to form unevenness inadvance on a surface of a film used as the exterior body 507. Theunevenness on the surface of the film increases flexibility of asecondary battery and further relieves stress. The depressions orprojections of a surface (or a rear surface) of the film formed byembossing form an obstructed space that is sealed by the film serving asa part of a wall of the sealing structure and whose inner volume isvariable. It can be said that the depressions or projections of the filmform an accordion structure (bellows structure) in this obstructedspace. Note that embossing, which is a kind of pressing, is notnecessarily employed and any method that allows formation of a relief onpart of the film is employed.

Note that one embodiment of the present invention is not limitedthereto. Various embodiments of the invention are described in thisembodiment and the other embodiment, and one embodiment of the presentinvention is not limited to a particular embodiment. For example,although an example of use of one embodiment of the present invention ina lithium-ion secondary battery is described, one embodiment of thepresent invention is not limited thereto. One embodiment of the presentinvention can be used for a variety of secondary batteries, a leadstorage battery, a lithium-ion polymer secondary battery, anickel-hydrogen storage battery, a nickel-cadmium storage battery, anickel-iron storage battery, a nickel-zinc storage battery, a silveroxide-zinc storage battery, a solid-state battery, an air battery, aprimary battery, a capacitor or a lithium ion capacitor, and the like.One embodiment of the present invention is not necessarily used for alithium-ion secondary battery.

The above is the description of the fabricating method example.

At least part of this embodiment can be implemented in combination withany of the other embodiments described in this specification asappropriate.

Embodiment 3

In this embodiment, a structure example of a battery suitable forapplication of being bent and unbent repeatedly is described.

FIG. 19A is a schematic top view of a battery 200. FIG. 19B is aschematic view of the battery 200 when seen from a direction of a dashedarrow in FIG. 19A. FIG. 19C is a schematic cross-sectional view takenalong line A1-A2 in FIG. 19A.

The battery 200 includes an exterior body 201, a stack 202 in theexterior body 201, and tabs 203 electrically connected to the stack 202and extending outside the exterior body 201. In the area surrounded bythe exterior body 201, an electrolyte solution is provided in additionto the stack 202.

The exterior body 201 has a film-like shape and is folded in half withthe stack 202 between facing portions of the exterior body. The exteriorbody 201 includes a folded portion 211, a pair of bonding portions 213,and a bonding portion 214. The pair of bonding portions 213 can eachalso be referred to as the side sealing portion. The bonding portion 214is positioned on the tab 203 side and can also be referred to as the topsealing portion.

Part of the exterior body 201 which overlaps with the stack 202preferably has a wave shape in which crest lines 221 and trough lines222 are alternately arranged. The bonding portions 213 and 214 of theexterior body 201 are preferably flat.

The stack 202 has a structure in which electrodes 231 and electrodes 232are alternately stacked. For example, the electrodes 231 each serve asone of a positive electrode and a negative electrode, and the electrodes232 each serve as the other thereof. Although not illustrated, aseparator may be provided between the electrode 231 and the electrode232.

As illustrated in FIG. 19C, in the folded portion 211, a space 225 ispreferably provided between the exterior body 201 and the stack 202.

FIG. 19D is a schematic cross-sectional view of the bent battery 200.Note that in FIG. 19D, some components are not illustrated.

When the battery 200 is bent, part of the exterior body 201 positionedon the outer side in bending is unbent and the other part positioned onthe inner side changes its shape as it shrinks. More specifically, thepart of the exterior body 201 positioned on the outer side in bendingchanges its shape such that the wave amplitude becomes smaller and thelength of the wave period becomes larger. In contrast, the part of theexterior body 201 positioned on the inner side in bending changes itsshape such that the wave amplitude becomes larger and the length of thewave period becomes smaller. When the exterior body 201 changes itsshape in this manner, stress applied to the exterior body 201 due tobending is relieved, so that the exterior body 201 itself does not needto expand and contract. As a result, the battery 200 can be bent by weakforce without damage to the exterior body 201.

As illustrated in FIG. 19D, the stack 202 changes its shape such thatthe relative positions of the electrodes 231 and the electrodes 232 areshifted. Here, the plurality of electrodes 231 and 232 in the stack 202are fixed on the bonding portion 214 side and thus changes their shapessuch that the relative positions of the electrodes 231 and theelectrodes 232 are more shifted at a position closer to the foldedportion 211. Thus, the stress applied to the stack 202 is relieved, sothat the electrodes 231 and 232 themselves do not need to expand andcontract. As a result, the battery 200 can be bent without damage to thestack 202.

Note that in the case of using a solid electrolyte or a gel electrolyte,when the entire stack 202 is covered with the electrolyte, the relativepositions of the electrodes 231 and the electrodes 232 are less likelyto be shifted, and therefore, relief of stress cannot be expected.Therefore, a plurality of stacks each including an electrolyte layerbetween the pair of electrodes 231 and 232 are preferably prepared andstacked. Thus, a structure can be obtained in which the relativepositions of the electrodes 231 and 232 are shifted even in the case ofusing a solid electrolyte or a gel electrolyte.

Furthermore, when a space 225 is provided between the stack 202 and theexterior body 201, the relative positions of the electrodes 231 and 232located inward from a neutral plane of the exterior body 201 can beshifted without being in contact with the exterior body 201.

In the battery exemplified in this embodiment, for example, the exteriorbody and the stack are less likely to be damaged and the batterycharacteristics are less likely to deteriorate even when the battery isrepeatedly bent and unbent.

At least part of this embodiment can be implemented in combination withany of the other embodiments described in this specification asappropriate.

EXAMPLE

A battery module was manufactured by the manufacturing method of oneembodiment of the present invention. Here, the method exemplified inModification Example 1 in Embodiment 1 (see FIGS. 3A to 3E) was used.

First, a lithium-ion secondary battery was prepared. The lithium-ionsecondary battery was fabricated using LiCoO₂ as a positive electrodeactive material, graphite as a negative electrode active material, andan embossed aluminum laminated film as an exterior body. An aluminumfoil was used for a positive electrode current collector, and a positiveelectrode active material layer was applied onto one surface thereof. Acopper foil was used for a negative electrode current collector, and anegative electrode active material layer was applied onto one surfacethereof. A surface opposite to the applied surface of the positiveelectrode current collector is provided in contact with that of anotherpositive electrode current collector. These positive electrode currentcollectors are sandwiched by a cellulose separator, and the celluloseseparator was molded into a bag-like shape. The molding was performed insuch a manner that polypropylene was sandwiched between portions of thecellulose separator which overlap with each other and subjected tothermocompression bonding. Similarly, a surface opposite to the appliedsurface of the negative electrode current collector is provided incontact with that of another negative electrode current collector. Then,six positive electrode current collectors and six negative electrodecurrent collectors were stacked such that the applied surface of thepositive electrode current collector faces the applied surface of thenegative electrode current collectors, whereby an electrode stack wasobtained. An aluminum laminated film is folded in half so as to sandwichthe electrode stack, and three sides were bonded. Bonding for formationof a bonding portion of the film was performed using a mold (heat bar).A heat bar with a flat surface was used for a side sealing portion, anda heat bar having a depression in part of a surface overlapping with atab was used for a top sealing portion.

As the exterior body, an aluminum laminated film with a thickness ofapproximately 50 μm in which polypropylene, aluminum foil, and nylon arestacked in this order was used. A wavelike film embossed so that thewave pitch was 2 mm and the height difference between a crest and atrough was 0.5 mm was used as the aluminum laminated film.

First, a first molding was performed to form a rubber molded body (thefirst portion) including a depression into which the lithium-ionsecondary battery was inserted. In the first molding, a millablefluorine rubber was used as a material to be molded. The molding wasperformed using a pressing cylinder having a diameter of 260 mm for 10minutes under conditions where the temperature was 170° C. and thepresser was 200 kgf/cm².

Next, the lithium-ion secondary battery was inserted into the depressionof the rubber molded body (the first portion).

Next, the rubber molded body and the lithium-ion secondary battery wereprovided in a metallic mold (a second mold) and subjected to secondmolding, so that the second portion was formed. The material in thefirst molding was used as a material to be molded. The second moldingwas performed using a pressing cylinder having a diameter of 260 mm for10 minutes under conditions where the temperature was 160° C. and thepresser was 30 kgf/cm².

Through the above process, the battery module including the lithium-ionsecondary battery in the rubber molded body was obtained.

Since the exterior body is molded in two steps (by first molding andsecond molding) in one embodiment of the present invention, thetemperature and the pressure can be made sufficiently high in the firstmolding. Therefore, the degree of freedom in conditions for molding thefirst portion which is a main portion of the exterior body is high, andthus formation under optimized conditions is possible. As a result, theexterior body can have better appearance and higher strength. Since thesecond portion can be formed in contact with only the vicinity of thetop sealing portion of the secondary battery in the second molding, thepressure for the molding can be made relatively high. Thus, defectivebonding or the like can be prevented.

FIG. 20A is a photograph of the fabricated battery module. As shown inthe photograph, the battery module can be bent easily by weak force.

FIG. 20B shows a state in which part of the exterior body is cut toexpose the secondary battery. Thus, it is confirmed that the exteriorbody of the secondary battery is not damaged and keeps the shape.

The above is the description of this example.

Note that this example can be implemented in combination with any of theother embodiments described in this specification as appropriate.

EXPLANATION OF REFERENCE

10:battery module, 20: exterior body, 21: first portion, 21 a: slit, 21b: slit, 21 c: slit, 22: second portion, 23: depression, 24: openingedge, 25: space, 26 a: hole, 26 b: hole, 30: battery, 30 a: battery, 31:exterior body, 32: tab, 33: circuit board, 34: FPC, 35: protectionmember, 35 a: plate portion, 35 b: plate portion, 35 c: bonding portion,41 a: first portion, 41 b: first portion, 42: second portion, 50 a:mold, 50 b: mold, 50 c: mold, 50 d: mold, 51 a: upper mold, 51 b: lowermold, 52 a: upper mold, 52 b: lower mold, 53: core, 54 a: core, 54 b:core, 55 a: injection hole, 55 b: injection hole, 60: battery module,61: band portion, 62: band portion, 63: holding portion, 64: operationbutton, 70: frame, 71: terminal, 72: terminal, 75: case, 80: electronicdevice, 81: housing, 82: display portion, 83: terminal, 84: terminal,90: battery module, 91: case, 91 a: top cover, 91 b: bottom cover,92:terminal, 94: depression, 95: first portion, 96: second portion, 97:exterior body, 102: secondary battery, 200: battery, 201: exterior body,202: stack, 203: tab, 211: folded portion, 213: bonding portion, 214:bonding portion, 221: crest line, 222: trough line, 225: space, 231:electrode, 232: electrode, 501: positive electrode current collector,502: positive electrode active material layer, 503: separator, 503 a:bonding portion, 504: electrolyte solution, 505: negative electrodecurrent collector, 506: negative electrode active material layer, 507:exterior body, 507 a: bonding portion, 507 b: side, 511: positiveelectrode, 511 a: region, 515: negative electrode, 520: sealing layer,521: positive electrode lead, 525: negative electrode lead.

This application is based on Japanese Patent Application serial no.2016-080389 filed with Japan Patent Office on Apr. 13, 2016, the entirecontents of which are hereby incorporated by reference.

The invention claimed is:
 1. A battery module comprising: a flexiblebattery having at least one tab projecting from a first side of theflexible battery; a first plate and a second plate with the flexiblebattery provided therebetween; and a flexible exterior body covering theflexible battery, the first plate, and the second plate, wherein a firstpart of the at least one tab projects from the flexible exterior body,and wherein the flexible battery, a first part of the first plate, and afirst part of the second plate are fixed to each other only in avicinity of the first side of the flexible battery.
 2. The batterymodule according to claim 1, wherein each of a second part of the firstplate and a second part of the second plate is not fixed to the flexiblebattery.
 3. The battery module according to claim 1, wherein the firstplate and the second plate have different lengths.
 4. The battery moduleaccording to claim 1, wherein the flexible exterior body comprises afirst slit into which the first plate fits and a second slit into whichthe second plate fits.
 5. The battery module according to claim 4,wherein when the flexible exterior body is bent, the first plate slidesalong the first slit and the second plate slides along the second slit.6. The battery module according to claim 1, further comprising a circuitboard, wherein the circuit board comprises terminals electricallyconnected to the at least one tab.
 7. An electronic device to beattached to the battery module according to claim 1, the electronicdevice comprising a housing, wherein the housing comprises a terminalelectrically connected to the at least one tab.
 8. A battery modulecomprising: a flexible battery having at least one tab projecting from afirst side of the flexible battery; a member having a first plateportion and a second plate portion bonded to each other with a bondingportion, the flexible battery provided between the first plate portionand the second plate portion; and a flexible exterior body covering theflexible battery and the member, wherein a first part of the at leastone tab projects from the flexible exterior body, and wherein theflexible battery and the bonding portion of the member are fixed to eachother only in a vicinity of the first side of the flexible battery. 9.The battery module according to claim 8, wherein each of the first plateportion and the second plate portion is not fixed to the flexiblebattery.
 10. The battery module according to claim 8, wherein the firstplate portion and the second plate portion have different lengths. 11.The battery module according to claim 8, wherein the flexible exteriorbody comprises a first slit into which the first plate portion fits anda second slit into which the second plate portion fits.
 12. The batterymodule according to claim 11, wherein when the flexible exterior body isbent, the first plate portion slides along the first slit and the secondplate portion slides along the second slit.
 13. The battery moduleaccording to claim 8, further comprising a circuit board, wherein thecircuit board comprises terminals electrically connected to the at leastone tab.
 14. An electronic device to be attached to the battery moduleaccording to claim 8, the electronic device comprising a housing,wherein the housing comprises a terminal electrically connected to theat least one tab.